Single element transducers can be mounted to one end of a probe for invasive imaging of blood vessels or cavities within the human body. By sending a voltage signal to the transducer through the probe, a piezoelectric material within the transducer is excited and generates acoustic signals propagating within the same plane of the excitation. The same piezoelectric material can also convert received acoustic signals into voltage signals. By rotating the probe along its longitudinal axis, a side-looking transducer can image a plane perpendicular to the longitudinal axis of the probe. The side-looking probe can be used in applications such as intravascular imaging. The signal element transducer may alternatively be mounted to one end of the probe to form a forward looking probe, that is, a probe for imaging in the same direction as the longitudinal axis of the cable. The forward looking probe can be used in applications such as rectal imaging. Multiple single element transducers may also be assembled into a sparse array (such as a basket type array) for applications such as mapping a heart chamber. Since the ultrasound probes are designed for invasive imaging, miniaturized ultrasound transducers may be utilized.
Wiring two electrodes of a single element transducer to the probe can be challenging due to the small size of the transducer. One approach is to attach the first electrode of the transducer to a substrate having a printed circuit, and manually apply silver epoxy to connect the second electrode to the substrate. However, this process lacks reproducibility and robustness. Since silver epoxy has high viscosity, therefore it is difficult to manually apply a controlled amount of epoxy. Silver epoxy also lacks robust adhesion to the substrate due to its high sensitivity to moisture and long curing time. Further, due to long touch time and cycle time, the process is not suitable for manufacturing disposable probes.